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From: TSS (216-119-143-74.ipset23.wt.net)
Subject: Britain: new findings point to larger outbreaks of vCJD "mad cow disease"
Date: August 18, 2004 at 6:55 am PST

-------- Original Message --------
Subject: Britain: new findings point to larger outbreaks of vCJD “mad cow disease”
Date: Wed, 18 Aug 2004 08:58:43 -0500
From: "Terry S. Singeltary Sr."
To: Bovine Spongiform Encephalopathy
CC: cjdvoice@yahoogroups.com


Britain: new findings point to larger outbreaks of vCJD “mad cow
disease”


By Trevor Johnson
18 August 2004

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UK scientists are upwardly revising their estimates of the number of
people likely to die from new variant CJD (vCJD, also known as “mad cow
disease”). It follows the death of a second patient, who contracted the
disease after a blood transfusion [1].

The patient, who had received a blood transfusion from a donor diagnosed
with vCJD in 1999, died five years later of a ruptured artery. An
autopsy revealed that the patient was infected with vCJD in the spleen
and lymph nodes.

The first case of a person being diagnosed with vCJD after a blood
transfusion occurred last year, prompting an investigation that revealed
another 17 people had received blood components from donors later
diagnosed as carrying vCJD.

New variant CJD affects the functioning of the brain, causing
personality change, loss of body function, and eventually death. It is
believed to have arisen due to people eating meat infected with bovine
spongiform encephalopathy (BSE). The BSE epidemic amongst cattle in the
UK reached its peak incidence in January 1993 at almost 1,000 new cases
per week.

BSE and vCJD are thought to be caused by a rogue form of proteins called
prions. All previous cases of the disease have been in people with a
particular set of markers on their prion proteins. People with this
genetic make-up comprise one third of the UK population. However, prions
in the latest case of the disease have a different set of markers, and
more than half the population shares these.

In Britain itself, 147 mainly young people have died of vCJD. It was
previously expected that this would rise to as many as 3,800. This
estimate was derived from examinations of appendix and tonsil tissues
removed from 12,674 people during routine surgery, of which three were
found to contain abnormal prion proteins. However, this estimate assumed
that only those with the less common set of markers were susceptible.
The latest case has proven that a larger proportion of the population
are susceptible to the disease than had previously been acknowledged.

Scientists expect that people with any of the three possible sets of
markers will eventually prove susceptible to vCJD, but the incubation
periods (the time during which the symptoms are not visible) are likely
to be different for each set.

The Conservative government at the time of the BSE epidemic, and the
Labour government that followed it, both limited their response to the
danger of vCJD to ordering the removal of the brain and spinal cord from
slaughtered cattle, rather than removing all UK beef from the food
chain. They did this on the grounds that consuming the blood and muscle
of infected animals could not transfer the disease.

There is now strong evidence that this assumption was also false.
Although the amount of infective agent in the blood is much smaller than
in other parts of the body, it cannot be regarded as safe.

The Blair government has been forced to acknowledge this by banning
people who have received blood transfusions from donating blood
themselves, so as to reduce the risk of vCJD being spread by this route.
This latest measure is in addition to the removal of white blood cells
from all blood used for transfusions, and the importing of blood
products such as clotting agents and plasma. At present, there is no
blood test to determine whether someone has the disease.

Professor Ironside, head of the CJD surveillance unit in Edinburgh that
researched this latest case of vCJD said, “This finding had major
implications for future estimations of numbers of vCJD cases in the
UK.... A very lengthy incubation period might explain why no clinical
cases of vCJD have yet been observed in this subgroup.”

He said that there could be other people in the subgroup (i.e. the group
of people with the same set of markers on their prions) carrying the
disease without being aware of it. They could still infect others with
vCJD, via blood transfusions, organ donations or reused surgical
instruments. He added, “It’s absolutely possible that there may be a new
epidemic, because the cases we’ve seen so far may only be those who are
unusually susceptible or have the shortest incubation periods. I’m not
in the business of scaremongering, but quite clearly the idea that this
problem is on the way out is unfortunately not the case at all.”

A group of researchers led by John Collinge at the Medical Research
Council’s prion unit in London believe their research with mice
strengthens the evidence that eating BSE-infected beef gives rise to
several types of brain disease, and that these include another kind of
CJD known as sporadic CJD, which had not previously been associated with
BSE.

The factors affecting one’s susceptibility to these infections are
complex, and involve other genetically determined characteristics
besides prion markers. The research indicates that there are at least
seven genes affecting the susceptibility of mice, and Collinge said that
it would be “pretty surprising” if it were not also the case in humans.

Frances Hall, secretary of the Human BSE Foundation, whose son Peter
died from vCJD in 1996, commented, “The hope was that only those of an
unusual genetic type would develop vCJD. Unfortunately it now looks like
more people could be susceptible. It’s still too early in the day to
know how many people will eventually end up with this disease.”

Note:
[1] “Preclinical vCJD after blood transfusion in a PRNP codon 129
heterozygous patient” (Lancet 2004; 264: 527-29) by Alexander H Peden,
Mark W Head, Diane L Ritchie, Jeanne E Bell, James W Ironside.

See Also:
BSE/Mad Cow Disease crisis provokes trade war

[2 August 2004]
Britain buys US plasma company due to continued vCJD threat

[30 December 2002]

http://www.wsws.org/articles/2004/aug2004/vcjd-a18.shtml

TSS





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